DESCRIPTION OF THE PRIOR ART
The substituted amidine compounds of the invention can be prepared by a modification of known methods. Typical methods which can be so modified include the reaction of a nitrile with a trialkyloxonium fluoroborate to prepare an N-alkyl nitrilium salt in a procedure similar to that of Meerwein et al., Ber. 89, 209 (1956), Borch, J. Org. Chem., 34, 627 (1969), and Weintraub et al. J. Org. Chem. 33, 1679 (1968). A number of N-monosubstituted and unsubstituted amidines are known. Craver et al. J. Pharm. Exptl. Therap. 99, 353 (1950); Netherlands Application 6,508,754, C.A. 65, 2181c (1966); U.S. Pat. Nos. 3,344,138, 3,417,122 and 3,334,137. Chlorobenzamidines are also known. Markwardt et al., Pharmazie, 1969, 24(7), 400-2, and European J. Biochem. 6; 502-6(1968).